make yasm generate cv8 debug data on win32

Native Windows targets should use CV8 format debugging symbols, not
DWARF.

Change-Id: I9489163fcd9d749b72f6c70ecbce67a6f0790802
diff --git a/build/make/configure.sh b/build/make/configure.sh
index c5885da..b65f3b7 100755
--- a/build/make/configure.sh
+++ b/build/make/configure.sh
@@ -890,7 +890,7 @@
         case  ${tgt_os} in
             win*)
                 add_asflags -f win${bits}
-                enabled debug && add_asflags -g dwarf2
+                enabled debug && add_asflags -g cv8
             ;;
             linux*|solaris*)
                 add_asflags -f elf${bits}